Control system for a rotary composter

ABSTRACT

A rotary composter is provided with a control system that is operable to control the operation of a rotary composter equipped with a variable rate air flow mechanisms and a variable speed drive for rotating the composter vessel. The control system includes a microprocessor in which is stored a look-up table to control the variable rate of application of both air flow and vessel rotation in response to sensed parameters corresponding to the operation of the composter. The control system further includes sensors at each digesting compartment within the composter vessel to provide information relating to the temperature within the vessel. Gas sensors detect the levels of carbon dioxide and ammonia within the air flow through the composter vessel. The microprocessor compares the temperature and gas data to permissible ranges therefor and determines if the composter is operating properly. In the event that operational changes are necessary, the microprocessor can effect the changes in speed of rotation of the vessel and the rate of air through the vessel either manually or automatically. To improve performance of the gas sensors, the composter vessel is provided with a smaller diameter sensor drum through which the air flow through the composter vessel can be discharged.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 08/660,136, filed Jun. 7, 1996 now abandoned.

BACKGROUND OF THE INVENTION

This invention relates generally to a machine for creating compost fromwaste material, such as manure and biodegradable garbage, and moreparticularly, to a control system for automating the operation of therotary composter for the biological degradation of organic wastematerials.

Rotary composters are well known in the art, as is represented by U.S.Pat. No. 5,407,809, issued to Larry J. Finn on Apr. 18, 1995. Theprocess achieves an accelerated biological degradation of the wastematerial to create compost therefrom. While any biodegradable materialcan be digested within the rotary composter, farm wastes, such as animalmanure, are of particular interests because of the desire to fix thenitrogen within the material to prevent stream pollution when thecomposted waste is spread onto the ground.

Present day manure handling techniques typically provide for acollection of the manure until weather and ground conditions areacceptable to permit the raw manure to be spread over the fields. Sincethe nitrogen within the raw manure has not been fixed, any runoff, suchas would occur following a storm, would have the potential for pollutingthe streams. Furthermore, free nitrogen in the form of nitrates canleach into the ground water supply and cause pollution. Accordingly,nonpoint sources of pollution, such as farming operations, have comeunder scrutiny with respect to manure handling.

The biggest problem with known rotary composters has been effectiveoperation. The vessel is preferably sized to process the waste materialwithin approximately three days. While the loading of waste materialinto the infeed end of the apparatus may be substantially continuous,actually on a periodic basis during the day, compost could be dischargedin the same manner. Accordingly, the vessel must be designed to retardmaterial flow through the vessel so that the material can be retainedfor at least three days. An adequate air supply must be provided throughthe vessel, as the biological degradation process is aerobic in nature,and the vessel must be designed to maintain a temperature ofapproximately 120 to 160 degrees fahrenheit, even in cold weatheroperation.

Efficient operation of the rotary composter is a function of controllingthe air flow and rotational speed of the vessel to maintain the propertemperatures within the vessel, as well as the proper levels of carbondioxide and ammonia gases emanating from the vessel from the compostingprocess. Accordingly, it would be desirable to provide a monitoringsystem that will sense the temperature and desired gas parameters of thecomposting process to provide an indication of adjustments that shouldbe made to the volume of air flow through the vessel or the rotationalspeed thereof. It would also be desirable to provide a control systemfor automating the operation of a variable flow air infeed mechanism anda variable speed rotational drive mechanism in response to thetemperature and gas levels sensed from the composting operation withinthe vessel.

SUMMARY OF THE INVENTION

It is an object of this invention to overcome the aforementioneddisadvantages of the prior art by providing a control system for theoperation of a rotary composter.

It is an advantage of this invention that the operation of a rotarycomposter can be monitored from a remote location.

It is another advantage of this invention that the operation of therotary composter can be automated.

It is a feature of this invention that the rotational speed and the rateof air inflow into the rotary composter can be controlled automaticallyin response to the sensed condition within the composter.

It is another feature of this invention that the operation of the rotarycomposter can be controlled by a microprocessor in response to thesensing of a given set of parameters relating to the composter'soperation.

It is still another feature of this invention that the variable speeddrive mechanism can be utilized to change the flow rate of materialthrough the rotary composter.

It is still another advantage of this invention that the speed ofoperation of the rotary composter can be selectively varied to adapt theoperation of the apparatus to accommodate variations in other externalfactors affecting the operation of the apparatus.

It is yet another advantage of this invention that both primary andauxiliary fan mechanisms can be operated at a variable speed to controlthe rate of the flow of air through the rotary composter vessel.

These and other objects, features and advantages are accomplishedaccording to the instant invention by providing a control system that isoperable to control the operation of a rotary composter equipped with avariable rate air flow mechanisms and a variable speed drive forrotating the composter vessel. The control system includes amicroprocessor in which is stored a look-up table to control thevariable rate of application of both air flow and vessel rotation inresponse to sensed parameters corresponding to the operation of thecomposter. The control system further includes sensors at each digestingcompartment within the composter vessel to provide information relatingto the temperature within the vessel. Gas sensors detect the levels ofcarbon dioxide and ammonia within the air flow through the compostervessel. The microprocessor compares the temperature and gas data topermissible ranges therefor and determines if the composter is operatingproperly. In the event that operational changes are necessary, themicroprocessor can effect the changes in speed of rotation of the vesseland the rate of air through the vessel either manually or automatically.To improve performance of the gas sensors, the composter vessel isprovided with a smaller diameter sensor drum through which the air flowthrough the composter vessel can be discharged.

BRIEF DESCRIPTION OF THE DRAWINGS

The advantages of this invention will be apparent upon consideration ofthe following detailed disclosure of the invention, especially whentaken in conjunction with the accompanying drawings wherein:

FIG. 1 is a top plan view of the rotary composter incorporating theprinciples of the instant invention, the cylindrical vessel beingmounted on a mobile trailer frame having a portion of the draw barbroken away for purposes of clarity;

FIG. 2 is a side elevational view of the rotary composter shown in FIG.1;

FIG. 3 is an enlarged top plan view of the drive mechanism located atthe infeed end of the rotary composter, corresponding to lines 3--3 ofFIG. 2;

FIG. 4 is a partial cross-sectional view of the drive mechanismcorresponding to lines 4--4 of FIG. 3, the vessel being shown inphantom;

FIG. 5 is an enlarged partial cross-sectional view of the rotarycomposter corresponding to lines 5--5 of FIG. 2 to depict the rotationalsupport of and the rotational drive rollers for the vessel on the mobiletrailer frame, most of the vessel structure being broken away forpurposes of clarity;

FIG. 6 is a partial cross-sectional view of the rotary compostercorresponding to lines 6--6 of FIG. 5 to depict the thrust bearingarrangement rotatably supporting the vessel on the mobile trailer frame;

FIG. 7 is a cross-sectional view of the rotary composter vessel takenalong lines 7--7 of FIG. 1, all drive mechanism and mobile trailer framesupports have been removed for purposes of clarity;

FIG. 8 is an enlarged elevational end view of the infeed end of therotary composter vessel corresponding to lines 8--8 of FIG. 7;

FIG. 9 is an enlarged elevational end view of the discharge end of therotary composter vessel corresponding to lines 9--9 of FIG. 7;

FIG. 10 is schematic view of the composter control system, the sideelevational view of the rotary composter vessel being broken away tomore clearly show the location of the sensors;

FIG. 11 is a schematic partial side elevational view of the infeed endof the rotary composter vessel with a sensor drum mounted thereto forthe discharge of air therethrough to enhance the effectiveness of thegas sensors used in the control system;

FIG. 12 is a schematic front elevational view of the infeed end of therotary composter seen in FIG. 11;

FIG. 13 is logic flow diagram for the control system;

FIG. 14 is a condition matrix table reflecting the differentcombinations of the parameters of temperature, carbon dioxide andammonia as detected by the sensors forming part of the control systemfor the rotary composter;

FIG. 15 is a key for the configuration of FIG. 15A and FIG. 15B; and

FIGS. 15A and 15B, when taken together in the manner depicted in FIG.15, show an input change table forming the look=up table for themicroprocessor to control air flow through the rotary composter vesseland rotational speed of the rotary composter vessel as a function of thecombination of parameters detected by the sensors of the control system.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the drawings and, particularly, to FIGS. 1 and 2, therotary composter incorporating the principles of the instant inventioncan best be seen. Left and right references are used as a matter ofconvenience and are determined by standing at the infeed end of thecylindrical vessel at the location of the drive mechanism and facing theremote discharge end thereof.

The rotary composter 10 is constructed as a generally cylindricaldrum-like vessel 11 rotatably supported on a wheeled trailer frame 15having a set of wheels 16 to permit movement of the composter 10 overthe ground G and a hitch member 18 to connect the trailer frame 15 to aprime mover. One skilled in the art will readily realize that themobility enabled by the wheeled trailer frame 15 is not a criticalfactor of the instant invention, as the wheels 16 need to be removedfrom the frame 15 when the composter 10 is set up for operation toprovide proper leveling and more stability for the operation of thecomposter 10.

The frame 15 does provide a support for the rotation of the drum 11, aswill be described in greater detail below, and further supports thedrive mechanism 20. The vessel 11 is inclined downwardly on the frame 15from the inlet or infeed end 13 toward the discharge end 14, preferablyat an angle of approximately one and a half degrees from horizontal.Preferably, the exterior circumference of the vessel 11, except for thetraction bands 12, is covered with a layer of polyurethane foam (notshown) to insulate the vessel 11 and retain heat generated by thecomposting process within the interior of the vessel 11.

Referring now to FIGS. 1-6, the drive mechanism 20 can best be seen. Thevessel 11 includes a pair of longitudinally spaced traction bands 12extending around the outer circumference of the vessel 11. The frame 15supports a pair of transversely spaced drive rollers 22, best seen inFIGS. 4 and 5, engaged with each of the traction bands 12 to effectrotation of the vessel 11. The drive mechanism 20 further includes amotor 25, preferably electrical, although other primary drive members,such as a hydraulic motor, could be equally used. The output shaft 26from the motor 25 is operably coupled to a reduction gear box 24 and apair of chain drives 28 that effect rotation of a corresponding pair ofdrive shafts 29 connected to the drive rollers 22 to effect the finaloutput speed of rotation of the vessel 11 at approximately one half of arevolution per minute or less.

Preferably, the motor 25 is variable in speed so that the speed ofrotation of the vessel 11 can be varied within the range of two and ahalf minutes per revolution to approximately thirteen minutes perrevolution of the vessel 11. Since the vessel 12 is inclined relative tohorizontal so that the rotation of the vessel 12 will move materialwithin the vessel toward the discharge end 14, each traction band 12 iscaptured by a thrust bearing 23, as best seen in FIG. 6, supported bythe frame 15 to prevent longitudinal displacement of the vessel 12relative to the frame 15.

Referring now to FIGS. 1, 2 and 7, it can be seen that the vessel 12 isdivided into a series of discrete compartments. Beginning at the infeedend 13, the first vessel compartment 31 is defined as the space betweenthe end wall 13a of the vessel 11 and the first baffle 36 and is adaptedfor receiving the material to be composted. The first or infeedcompartment 31 is provided with an access door 35 formed within theexterior circumference of the vessel 11 to permit the introduction ofmaterial within the infeed compartment 31 to be composted. The accessdoor 35 is preferably slidable between an opened position and a closedposition to prevent the spilling of material from the infeed compartment31 as the vessel 11 rotates.

The last compartment 34 at the discharge end 14 of the vessel 11 isdefined as the space between the discharge end wall 14a and the lastbaffle 38. The last or discharge compartment 34 is provided with fourdischarge doors 39 equally spaced around the circumference of the vessel12. The discharge doors 39 are also preferably of the slidable varietythat can be moved between opened and closed positions to control thedischarge of compost therefrom. The opening of the discharge doors 39will allow the compost within the discharge compartment 38 to spilltherefrom as the vessel 11 is rotated. Between the infeed compartment 31and the discharge compartment 38, the vessel 11 is divided into aplurality, preferably four, digesting compartments 33 separated by aninterior baffle 37.

The interior baffles are constructed as a truncated disc that coversapproximately 85 percent of the cross-sectional area of the vessel 11.The passageway 37a formed by the missing segment of the circulardisc-like baffle 37 is oriented 120 degrees out of phase with theimmediately succeeding or preceding baffle 37. When one passageway isoriented at an azimuth of approximately 60 degrees, the next passagewayis located at an azimuth of approximately 300 degrees. Likewise, thenext two interior baffles have the passageway oriented at an azimuth ofapproximately 180 degrees and back at 60 degrees, respectively.

The first baffle 36 is preferably constructed with an eccentric opening36a through the center of the baffle. The eccentric opening 36a forms aweir that prevents all of the material from moving from the firstcompartment 31 into the adjacent first digesting compartment 33a. As aresult, a portion of the microbes that effect the composting activitywithin the vessel 11 will be retained within the infeed compartment 31to inoculate the material subsequently introduced through the infeedopening 35 to start the composting process before the material evenmoves into the first digesting compartment 33a. Similarly, the lastbaffle 38 has a concentric opening 38a therethrough to provide a weir toretain a microbial inoculant within the last digesting compartment 33d,thereby insuring that the digesting compartments contain at least aminimum supply of microbes to hasten the digesting or compostingprocess.

Material to be composted is loaded through a suitable means (not shown)into the first compartment 31 and passes slowly from one digestingcompartment to the next digesting compartment until reaching thedischarge compartment 34. One skilled in the art will recognize thatonly small amounts of material in one digesting compartment 33 pass intothe succeeding digesting compartment 33 on each revolution of the vessel11. Further since the speed of rotation of the vessel 11 is in the orderof a half of a revolution or less per minute, one skilled in the artwill recognize that the vessel 11 can retain material within therotating vessel 11 for three or more days from the time it is fed intothe infeed compartment 31 and is discharged from the dischargecompartment 34.

Referring now to FIGS. 1 and 7-9, the air infeed mechanism 50 can bestbe seen. A supply of ambient air is fed into the discharge compartment34 to be pushed through the vessel 11 to exit at the screened opening 54in the infeed opening 31. The staggered arrangement of the interiorbaffles 37, as described above, requires that the air fed into thedischarge compartment 34 will necessarily follow a serpentine path toreach the infeed compartment 31. The spiraled movement of air throughthe vessel 11 facilitates the interaction of the air through thematerial within the digesting compartments 33. The direction of the flowof air through the vessel 11 is opposite to the direction of materialflow through the vessel 11 in order to reduce the temperature of thematerial within the discharge compartment 34 and to transfer heat intothe digesting compartments 33.

A blower 51 supported on the trailer frame 15 forces air through thepipe 52 that extends around the exterior of the vessel 11 to the centerof the discharge end 14 of the vessel 11 to inject air into thedischarge compartment 34. The pipe 52 passes through and is sealedagainst the discharge end wall 14a to terminate a short distance fromthe discharge end wall 14a into the discharge compartment 34 to definean air infeed port 53. The pipe 52 is fixed relative to the frame 15 andthe vessel 11 rotates relative to the pipe 52.

The air infeed port 53 is surrounded by an air diffuser 55 formed as acone pointed at the infeed end 13 of the vessel 11. The diffuser 55 isformed with a plurality of holes 59 therein to allow the passage of airtherethrough from the air infeed port 53 which terminates near thecenter of the conical shape of the diffuser 55. The symmetrical conicalshape of the diffuser 55 presents a uniform surface to the materialaccumulated within the discharge compartment 34 during the rotation ofthe vessel 11. The diffuser 55 is provided with a mounting bracket 56that is detachably connected to the discharge end wall 14a by connectors57.

By presenting a sloped surface to the material accumulated within thedischarge compartment 34 and a spaced distance away from the dischargeend wall 14a, material will not significantly accumulate on the diffuser55. Furthermore, the holes 59 formed in the diffuser 55 are of a size toprevent the passage of large particles or clumps of material frompassing through the diffuser 55 and plugging the air infeed port 53. Anymaterial passing through the holes 59 can either pass back through theopposing holes 59 or slide off the interior sloped surface of thediffuser 55 to pass between the diffuser 55 and the discharge end wall14a. As a result, material will not accumulate within the diffuser 55 toplug the air infeed port 53.

Preferably, the vessel 11 is approximately seven feet in diameter andapproximately thirty-four feet in length. The vessel 11 is divided intosix compartments, including the infeed compartment 31, the dischargecompartment 34 and four interior digesting compartments 33. Preferably,the infeed compartment 31 will be the largest of the compartments andeach subsequent compartment 33, 34 will be smaller in size such that thedischarge compartment 34 is approximately half the size of the infeedcompartment 31. Each interior baffle 37 is provided with a passageway37a formed by a missing segment that measures approximately one and ahalf feet along the radius of the vessel 11.

The interior surface of the vessel 11 is provided with a plurality ofcircumferentially spaced lifter ribs 19 that extend radially into theinterior of the vessel 11 about one and one half inches and are spacedapart about six inches around the circumference. When the vessel 11 isrotating, the segmented openings 37a offset around the circumference ofthe vessel 11 act like a large screw. As the lifter ribs 19 elevate thematerial in small increments through the passageways 37a into thesubsequent compartment 33 on each rotation of the vessel 11. The weirformed by the central opening 38a in the last baffle 38 maintains alevel of material within the vessel 11 to ensure that none of thecompartments 33 can be completely emptied so that an inoculum isretained in each compartment to provide a staged microbiological culturefor each of the compartments.

Air is supplied by a semi-pressure blower 51 to a center connection withthe discharge end wall 14a. When the discharge doors 39 are closed, thevessel 11 is substantially sealed so that air is forced through thecomposting materials in the successive compartments 34, 33, 31 to bedischarged through the screened opening 54. The blower 51 can be adouble fan configuration or a variable speed fan so that the rate of airflow can be selectively varied. The direction of the flow of air iscounter to the direction of the flow of the composting material throughthe vessel 11. Since the successive passageways 37a arecircumferentially offset by 120 degrees, the air must move down throughone passageway 37a and then around to the next passageway 37a and so onuntil passing through all four digesting compartments 33. Furthermore,the lifter ribs 19 elevate the composting material at the passageways37a when overlapping the void 40 past the angle of repose, incorporatingair as the material sloughs over in the void 40.

The time of passage of material through the vessel 11 is of criticalimportance. The material within the digesting compartments must achievethermophylic temperatures, i.e. approximately 150 degrees F., althoughthe material discharged from the discharge compartment may havetemperatures reduced to the mesophilic range, i.e. less than 100 degreesF. Start-up procedures will include the passage of the initiallyintroduced materials back into the infeed compartment for re-processinguntil the materials have reached the thermophylic temperatures and thecomposting of the materials has been completed. Once the start-upprocedure has been completed, material need only pass through the vessel11 one time, provided that thermophylic temperatures have been achieved.

An equipment failure that disrupts the composting process, such as afailure in the drive mechanism 20, may require a modified start-up orrecovery procedure to be utilized to achieve the aggressive compostingof the material. An interruption of the operation of the composter 10 asshort as three days will require the use of a recovery procedure tore-establish the aggressive composting process. Likewise, regular infeedof new materials to be composted is necessary to maintain the aggressivecomposting process. The failure to add fresh materials for two days hascaused a decline in the composting activity.

Material can be discharged from the discharge compartment 34 duringrotation of the vessel 11 simply by opening the discharge doors 39 andcollecting the material discharged therefrom. Preferably, a secondconveyor (not shown) will be positioned to collect the dischargedcompost and convey the compost to a preselected location for cool downand subsequent disposition. For compost formed from animal wastes, thenitrogen in the compost is fixed and the compost can be spread directlyonto the fields without fear of contamination of the water supply fromrunoff or leaching into the ground water.

Referring now to FIGS. 10-15, the automated control mechanism 60 canbest be seen. The control mechanism 60 includes a plurality of sensors,including a temperature sensor 62 for each of the digesting compartments33 and a temperature sensor 63 for the air flow discharged from thevessel 11. The temperature sensors 62 are fixed to the vessel 11 to berotated therewith. As a result, the lines from the sensors 62 areconnected to a conventional slip ring 65 to permit the transmission ofdata from the rotating sensors 62 to stationary lines for transfer to amicroprocessor 75. A sampling port 67 is stationarily mounted to draw asample of the air discharged from the vessel into both an ammonia sensor68 and a carbon dioxide sensor 69, which can be positioned remotely fromthe vessel 11, to provide an indication of the levels of ammonia andcarbon dioxide in the air flow discharged from the vessel 11. Data linestransmit information from the ammonia and carbon dioxide sensors 68, 69to the microprocessor 75.

As best seen in FIGS. 10-12, the vessel 11 is provided with a sensordrum 70 mounted to the exterior of the vessel 11 around the screenedopening 54 in the infeed endwall 13a for rotation with the vessel 11.The temperature sensor 63 and the sampling port 67 are mounted in astationary manner through an opening 71 in the end of the sensor drum 70to obtain an appropriate sampling of the air flow discharged from thevessel 11 before the discharged air gets dissipated into the atmosphere.The sensor drum is provided with an open port 73 located next to thevessel 11 to allow any debris to fall out of the sensor drum 70 as itrotates with the vessel 11. The material that might be in the sensordrum 70 would most likely have passed into the sensor drum 70 throughthe screen opening 54 in the vessel 11.

Returning now to FIGS. 10 and 13-15, the microprocessor 75 is preferablyan input analog (IASSC) computer that receives input information fromthe temperature sensors 62, 63, the gas sensors 68, 69, an ambient airtemperature sensor 76, the speed of rotation of the vessel 11 from thedrive mechanism 20 and the rate of air flow from the air infeedmechanism 50. In addition, the IASSC computer 75 is preferably housed ina protective box (not shown) in which a temperature sensor 77 is mountedto monitor the environment temperature for the computer 75. The IASSCcomputer 75 can be accessed from an immediate display 78, such as a laptop computer, or through a modem 79 that permits a remote monitoringthrough the telephone lines.

Desired ranges of the temperature, ammonia and carbon dioxideparameters, which may vary with respect to the material being composted,are stored within the IASSC computer 75. The microprocessor 75frequently monitors these parameters and compares the sensed values withthe desired ranges and makes a determination as to whether eachparameter is within, above or below the respective desired range. Theresultant determination can be reflected in the condition matrixdepicted in FIG. 14, from which the microprocessor 75 can refer to alook-up table depicted in FIG. 15 to display the corrective action to betaken.

The microprocessor 75 can be programmed to allow corrective action withrespect to the air flow and the rotational speed of the vessel 11 to betaken automatically. With an appropriate material infeed mechanism (notshown), the microprocessor 75 may be able to add incremental amounts ofmaterial as reflected in the look-up table of FIG. 15. Accordingly, theoperative control of the rotary composter 10 can be at least partiallyautomated. Preferably, the microprocessor 75 can store three days worthof data from the various sensors to permit the periodic display and/ordownloading of the data to permanent files, as opposed to real-timemonitoring of the data or automation of the operative controls.

The microprocessor 75 can also be programmed to call through a list ofphone numbers in the event an operating parameter moves outside therespective desired range to permit an immediate manual correction of theoperation of the rotary composter 10, in which case the look-up table ofFIG. 15, or the appropriate portion thereof, can be displayed to assistthe operator in determining the appropriate corrective action toundertake.

The logic flow diagram relating to the automated operation of the rotarycomposter 10 by the microprocessor 75 is depicted in FIG. 13. Themicroprocessor 75 receives in step 81 data input from the varioussensors 62, 63, 68, 69 and 76, as well as data input information fromthe air infeed mechanism 50 and the drive mechanism 20 and analyzes instep 82 the data to determine if the data fits within the respectivedesired ranges. If the data received indicates in step 83 that thesystem is operating properly, then the microprocessor continues a loopthrough steps 81, 82 and 83.

In the event that one of the data inputs falls outside the correspondingdesired range, the microprocessor determines in step 83 that the systemin not operating properly. In step 84, the microprocessor 75 determines,from the condition matrix depicted in FIG. 14, the condition of thecomposter 10. In step 85, a query is made as to whether there has been achange in the position within the condition matrix. If not, a counter inincremented. If so, then the counter is reset to zero. The counter isreflected in the look-up table depicted in FIG. 15 as either "Counter="or "C=" and provides a means by which action can be delayed for severalcycles.

In step 86, a query is made as to whether there has been any change inthe condition since the last cycle. If a change in the sensed conditionhas occurred, a subsequent query is made in step 87 as to whether thechange is in the direction toward placing the wayward parameter into thecorresponding desired range. If yes, then the controls are not changedand another cycle is instituted. If not, then the operating parameters,including fan speed and rotational speed of the drum, are returned tothe previous setting and another cycle in instituted. Because of theslow rotational speed of the vessel 11 and the slow response time toregister any changes in the condition of the compost or the operation ofthe composter, each cycle needs to be spaced at 10 to 15 minuteintervals and perhaps longer under cold weather conditions. In fact, themicroprocessor 75 can utilize the sensed ambient air temperature to varythe cycle intervals, with colder weather requiring longer cycleintervals.

If the result of the query as to the change in the condition since thelast cycle is negative, the microprocessor 75 refers to the look-uptable depicted in FIG. 15 and effects the necessary changes to the airinfeed mechanism 50 and drive mechanism 20, and, if applicable, effectsthe necessary changes to the material being fed into the infeedcompartment 31 at step 88. After the changes are effected, the cycle isstarted again at step 81.

Accordingly, the control system 60 has the ability to provide monitoringof the system for manual manipulation or the ability to automaticallyvary selected control functions. The ability to monitor or to effectcontrol can be accomplished on-site or from a remote location. Somefunctions of the rotary composter 10 can be controlled by direct dial-inover the telephone with a touch tone phone.

It will be understood that changes in the details, materials, steps andarrangements of parts which have been described and illustrated toexplain the nature of the invention will occur to and may be made bythose skilled in the art upon a reading of this disclosure within theprinciples and scope of the invention. The foregoing descriptionillustrates the preferred embodiment of the invention; however,concepts, as based upon the description, may be employed in otherembodiments without departing from the scope of the invention.Accordingly, the following claims are intended to protect the inventionbroadly as well as in the specific form shown.

Having thus described the invention, what is claimed is:
 1. A controlsystem for a rotary composter having a vessel divided into a pluralityof digesting compartments, a drive mechanism for effecting rotation ofthe vessel, an air infeed mechanism for providing a flow of air throughthe vessel, and means for feeding material to be composted into thevessel, comprising:temperature means for sensing the temperature in eachof said digesting compartments, said temperature means including atemperature sensor being affixed to said vessel in each said digestingcompartment to be rotatable with the vessel; discharge means fordirecting the flow of air passing through said vessel externally of saidvessel; gas means for sensing predetermined gases in said air flow, saidgas means includes a sampling port mounted on said vessel within astream of air being discharged through said discharge means to direct asampling portion of said air flow to gas sensors to detect the level ofcarbon dioxide and ammonia within said air flow; processing meansoperatively connected to said temperature means and said gas means toaccept data provided by said temperature means and said gas means andcompare said data to predetermined ranges for such data stored in saidprocessing means; and indicator means operatively associated with saidprocessing means to indicate when such data is outside of thecorresponding predetermined range for such data.
 2. The control systemof claim 1 wherein said processing means includes a look-up tablesuggesting corrective action to take for a condition matrixcorresponding to the different combination of data received relative tothe corresponding predetermined ranges.
 3. The control system of claim 2wherein said air infeed mechanism and said drive mechanism are variablyoperable, said processing means being operably connected to said airinfeed mechanism and said drive mechanism to permit said processingmeans to control the operation thereof.
 4. The control system of claim 3wherein said air infeed mechanism and said drive mechanism can becontrolled manually through said processing means from a remotelocation.
 5. The control system of claim 3 wherein said air infeedmechanism and said drive mechanism can be controlled by said processingmeans in response to the corresponding suggested actions from saidlook-up table.
 6. The control system of claim 3 wherein said processingmeans collects data from said temperature sensors and said gas sensorsin cycles spaced in time by a cycle interval.
 7. The control system ofclaim 6 further comprising an ambient temperature sensor to sense theambient air temperature, said processing means varying said cycleinterval as a function of the sensed ambient temperature.
 8. A controlsystem for a rotary composter having a vessel divided into a pluralityof digesting compartments, a drive mechanism for effecting rotation ofthe vessel, an air infeed mechanism for providing a flow of air throughthe vessel, and means for feeding material to be composted into thevessel, comprising:temperature means for sensing the temperature in atleast one of said digesting compartments; gas means for sensingpredetermined gases in said air flow, said gas means including asampling port to direct a portion of said air flow to gas sensors todetect the level of carbon dioxide and ammonia within said air flow; asensor drum rotatable affixed to said vessel and being mounted such thatthe air flow discharged from said vessel must pass through said sensordrum, said sampling port being positioned within said sensor drum toobtain a sampling of said air flow before being dissipated into theatmosphere; processing means operatively connected to said temperaturemeans and said gas means to accept data provided by said temperaturemeans and said gas means and compare said data to predetermined rangesfor such data stored in said processing means; and indicator meansoperatively associated with said processing means to indicate when suchdata is outside of the corresponding predetermined range for such data.9. The control system of claim 8 wherein said vessel is further providedwith a slip ring operably connected to said temperature sensors topermit said rotating temperature sensors to transmit data to astationary line connected to said processing means.
 10. In a rotarycomposter having a vessel divided into a plurality of digestingcompartments, a drive mechanism for effecting rotation of the vessel, anair infeed mechanism for providing a flow of air through the vessel, andmeans for feeding material to be composted into the vessel, theimprovement comprising:a control system for monitoring the operation ofsaid rotary composter, particularly the temperature of the materialbeing composted within said digesting compartments and the level ofcarbon dioxide and ammonia gases emanating from the material beingcomposted and being discharged with the flow of air through the vesselthrough a discharge means in said vessel for directing said flow of airexternally of said vessel, said control system including:temperaturesensors for sensing the temperature of the material within saiddigesting compartments; gas sensors for sensing the level of carbondioxide gas and ammonia gas within said air flow, said gas sensors beingoperatively associated with a sampling port mounted on said vessel andbeing operable to extract a sampling portion of the flow of air beingdischarged from said vessel and direct said sampling portion to said gassensors; processing means operatively connected to said temperaturesensors and said gas sensors to accept data provided by said temperaturesensors and said gas sensors and compare said data to predeterminedranges for such data stored in said processing means; and indicatormeans operatively associated with said processing means to indicate whensuch data is outside of the corresponding predetermined range for suchdata.
 11. The rotary composter of claim 10 wherein said air infeedmechanism and said drive mechanism are variably operable, saidprocessing means being operably connected to said air infeed mechanismand said drive mechanism to permit said processing means to control theoperation thereof.
 12. The rotary composter of claim 11 wherein said airinfeed mechanism and said drive mechanism can be controlled manuallythrough said processing means from a remote location.
 13. The rotarycomposter of claim 11 wherein said air infeed mechanism and said drivemechanism can be controlled by said processing means in response to thecorresponding suggested actions from a look-up table stored in saidprocessing means.
 14. The rotary composter of claim 11 wherein saidvessel is further provided with a slip ring operably connected to saidtemperature sensors to permit said rotating temperature sensors totransmit data to a stationary line connected to said processing means.15. The rotary composter of claim 11 wherein said processing meanscollects data from said temperature sensors and said gas sensors incycles spaced in time by a cycle interval, said control system furtherincluding an ambient temperature sensor to sense the ambient airtemperature, said processing means varying said cycle interval as afunction of the sensed ambient temperature.
 16. A rotary compostercomprising:a vessel divided into a plurality of digesting compartments;a drive mechanism for effecting rotation of the vessel; an air infeedmechanism for providing a flow of air through the vessel; means forfeeding material to be composted into the vessel; a control system formonitoring the operation of said rotary composter, particularly thetemperature of the material being composted within said digestingcompartments and the level of carbon dioxide and ammonia gases emanatingfrom the material being composted and being discharged with the flow ofair through the vessel, said control system including:temperaturesensors for sensing the temperature of the material within saiddigesting compartments; gas sensors for sensing the level of carbondioxide gas and ammonia gas within said air flow, said gas sensors beingoperatively associated with a sampling port mounted on said vessel andbeing operable to extract a sampling portion of the flow of air beingdischarged from said vessel and direct said sampling portion to said gassensors; processing means operatively connected to said temperaturesensors and said gas sensors to accept data provided by said temperaturesensors and said gas sensors and compare said data to predeterminedranges for such data stored in said processing means; and indicatormeans operatively associated with said processing means to indicate whensuch data is outside of the corresponding predetermined range for suchdata; and a sensor drum affixed to said vessel to be rotatabletherewith, said sensor drum being mounted such that the air flowdischarged from said vessel must pass through said sensor drum, saidsampling port being stationarily mounted through an opening within saidsensor drum to obtain a sampling of said air flow before beingdissipated into the atmosphere.
 17. A rotary composter comprising:avessel divided into a plurality of digesting compartments; a variablespeed drive mechanism for effecting rotation of the vessel; a variablespeed air infeed mechanism for providing a flow of air through thevessel to be discharged from a discharge opening in said vessel; and anautomated control system for monitoring the operation of said rotarycomposter, including:temperature sensors for sensing the temperature ofthe material within said digesting compartments; a sampling port forcollecting a sample of the air flow through said vessel near saiddischarge opening; a carbon dioxide gas sensor operably connected tosaid sampling port for sensing the level of carbon dioxide gas withinsaid air flow; an ammonia gas sensor operably connected to said samplingport for sensing the level of ammonia gas within said air flow; and amicroprocessor operatively connected to said temperature sensors andsaid carbon dioxide and ammonia gas sensors to accept data providedthereby, to compare said data to predetermined ranges for such datastored in said microprocessor, to determine the condition of said datawith respect to a condition matrix, and to determine corrective actionto undertake relative to the condition matrix from a look-up tablestored in said microprocessor, said microprocessor further beingconnected to said air infeed mechanism and said drive mechanism toeffect a modification of the speed of operation of said air infeedmechanism and of said drive mechanism, selectively, as defined per thecorrective action of said look-up table; and a sensor drum affixed tosaid vessel to be rotatable therewith, said sensor drum being mountedsuch that the air flow discharged from said vessel must pass throughsaid sensor drum, said sampling port being stationarily mounted throughan opening within said sensor drum to obtain a sampling of said air flowbefore being dissipated into the atmosphere.